Telescoping slide for extension tables



Aug. 22, 1967 EDELSON TELESCOPING SLIDE FOR EXTENSION TABLES 2 Sheets-$heet 1 Filed Feb. 8, 1966 INVENTORL Z 60 [ale/son Afr/bur 4. Marc/7 Aug. 22, 1967 L. EDELSON 3,336,332

' TELESCOPING SLIDE FOR EXTENSION TABLES Filed Feb. 8, 1966 2 Sheets-Sheet 1 N VEN'IOR.

[e0 fae/Jon 4r/hur 4 March 4 770a NE) United States Patent 3,336,882 TELESCOFING LlDE FOR EXTENSION TABLES Leo Edeison, Mamaroneck, N.Y., assignor to Columbian Slides Inc, Freeport, N.Y., a corporation of New York Filed Feb. 8, 1966, Ser. No. 525,?63 7 Claims. (Cl. 108-83) This invention relates to sliding supports applicable to tables composed of sections capable of being extended for purposes of increasing their size by allowing the insertion of leaves between the extended table sections. In particular, this invention involves a sheet metal slide assembly with the novel construction that prevents sagging of the central area of the extended table.

The prior art teaches the construction of varieties of slides that may be applied to table sections to allow the latter to be extended so as to increase their size or area. Such slides may be of different shapes, forms, and designs, and are attachable to the table sections in numerous different ways. For example, a typical slide may be constructed of a series of channel members which mesh with one another in the manner which allows the extended length of the slide to be equivalent to the sum of the separate lengths of the channels. On the other hand, the contracted length of such a slide does not exceed the approximate length of any one of the separate channels. Variations in the design of such a slide are possible by employing nonuniform lengths by which the channel members engage with one another, and different means for supporting the channel sections in relation to one another. In a typical situation these slides are mounted beneath the table surface, and connect the two sections of the table which are to be separated when the table area is to be increased. When the slide is in the contracted state, the two sections of the table are in contactgenerally at the mid-section, and together form a firm table surface. When the table is to be extended, the two sections are drawn apart and the slide is forced into its extended state. Under these circumstances the distance between table legs is increased when measured in the vertical plane through the longitudinal axis of the slide. Accordingly, the extension of the tablesections uncovers the area between the extended sections and leaves a portion of the slides exposed when viewed from the top of the table surface. This exposed surface area may be subsequently covered by sections commonly referred to as leaves which resemble in substance the extended sections of the table. When these leaves are inserted between the extended table sections, they combine to form a complete and continuous table surface.

Heretofore when such a table was extended, sagging often resulted and the top surface became concave. This in turn led to jamming of the slides and undesirable ap pearance of the table and all the difliculties associated with a table surface which is non-horizontal or nonplanar. The diificulty increased when any load was applied to the table.

It is therefore an object of the present invention to provide a slide of such construction that sagging of the extended table with or without loads will not occur.

Another object of the invention is to provide an extensible table which will not deform in any way after the removal of a load thereupon.

The present invention comprises an interlocking and telescoping slide that has a longitudinally curved arch, the convex side of which faces upwardly when the slide is attached to the under side of a table top Two or more such slides can be nested together to provide an arch on which leaves can be supported when the sections of the table are pulled apart. The weight of the leaves tends to flatten out the arch rather than to produce a sag in the slide members as has been true of prior structures.

Other objects and advantages are set forth in greater detail in the following specifications taken in conjunction with the accompanying drawing in which:

FIGURE 1 is a perspective view of a typical assembly of table and slides;

FIGURE 2 is a perspective view of the slide of the present invention;

FIGURE 3 is 21 FIGURE 2;

FIGURE 4 shows a method by which the slides may be mounted to the table through the application of brackets;

FIGURE 5 is a front view of the table showing the state of the slides when the table sections are drawn apart;

FIGURE 6 is a front view of the table showing the state of the slides when the table is contracted and at its minimum size.

In accordance with FIGURES 1 through 3, a typical extensible table includes two separable sections 1 and 2. Each section is equipped with two leg supports 3. The two table sections are joined or coupled together by slides 4 generally fastened to the underside of the table top 5. FIGURE 1 shows the application of three slides to perform the desired function of extending the table. However, any number of slides (two or more) may be employed depending upon the size of the table, the desired rigidity and extension.

When the table is not extended and the table top is to occupy minimum area, edge 6 of the table corresponding to section 1 is in contact with edge 7 of section 2. These two sections may be caused to further mate well so as to form a continuous top surface, by providing for dowels 8 to slide into openings 9 as the two sections are brought together. When the two sections are drawn apart, the open area left between edges 6 and 7 may be covered by leaves 10 and 11. These leaves are madeof the same substance as the table top, and may be placed so that they rest upon and are supported by the slides. The leaves may also be equipped with dowels and corresponding holes so that a well mated interface is obtained. Although two leaves are shown in FIGURE 1, any number of one or more is possible depending upon the design desired.

The slide 4 when extended appears as shown in FIG- URE 2. The slide is typically constructed of sheet metal channels which interlock with one another and the channel members slide longitudinally in relation to one another. When extended, channels 12, 13, and 14 compensate for the separation of the two table sections and provide the support required to maintain the two sections in their upright positions.

Brackets 17 are provided to fasten the slides to the table top although other techniques for performing this function are possible.

Each of the channels is constructed so that the longitudinal axis includes a curvature which is concave when viewed from beneath the table surface and the slide is mounted in place.

I It is well known in structural mechanics that whena structure such as the slide is supported at both ends rather than in the center, the slide and the leaves applied thereover will tend to deflect particularly in the center. Many difficulties have been encountered by such deflection. This deflection has been responsible for the sagging effect experienced in extensible tables. When, for examcross-sectional view of the slide of pie, the two sections of the table are drawn apart, the

slide is in the state where it is extended and supported at both ends due to its mountings under the table top. If subsequently the leaves are applied to cover the area left vacant the slides may deflect so as to produce a convex surface when viewed from beneath the table top. This deflection is increased when weights or loads are applied to the table tops. The magnitude of the deflection or sag at any point along the slide is, in fact, proportional to the size of the load represented by the weights of the objects.

If consequently, the slide is constructed so that its longitudinal axis has a concave curvature when viewed from beneath the table, any deflection of the slide with or without loading of the table will tend to force the longitudinal axis into a straight line. With the longitudinal axis tending towards this direction therefore, sagging of the slides and hence the table surface, will not prevail. The built-in curvature of the slides may therefore be looked upon as producing a pre-stressed effect which compensates for the deflection resulting from the loading of the slides. It is this novel curved construction of the slides which eliminates the sagging effect that has heretofore prevailed in the application of extensible tables.

Extensive experimentation of slides with tables of different sizes had demonstrated that five different sizes of slides-l8", 21, 26", 32" and 42" will accommodate the range of table configurations that are normally encountered. It has been found further, that associated with each of these sizes is an optimum number of channel members. Thus, for the 18" and 21 sizes, 4 or 5 compatible members form an optimum combination. For the range of sizes between 26" and 42", 3 or 4 compatible members have been found to be the preferred arrangement.

FIGURES 5 and 6 compare the relative magnitudes of the are when the table is in its extended and contracted states respectively. As shown by these diagrams, the size of the are measured by the height h, increases with the length of the extended slide. The slide when mounted in place, is pro-stressed so that the surface of the slide in contact with the underside of the table top, is in compression. This particular pre-stressed state of the slide continues to prevail upon its extension due to the drawing apart of the table sections. When subsequently a load is applied to the central area of the table and transmitted to the slides, the amount of pre-stressing is reduced, and this compensates for the load deflection that would ordinarily result in the sagging of the table.

The size of the arc or curvature of the slides so as to produce the pre-stressed effect, is dependent upon the size of the slides. The magnitude of the arc is classified for different sizes of slides when these are extended over a length of 38 to 42 inches. Corresponding to the 18 slides, the optimum height of the arc lies within the range of 0.50" to 0.150" at the center point when the slides are extended to the aforementioned length of 38 to 42 inches. For the 21", 26", 32", and 42" slides, the corresponding heights of the arc lie within the ranges of 0.075" to 0.175", 0.100 to 0.200", 0.150" to 0.300", and 0.200" 0.400" respectively. The height of the arc is also dependent upon the gage of the metal employed in the construction of the slides. Within the numerical limits of the indicated ranges of values, the lighter the metal gage, the greater the arc to be used in the construction of the slides.

The optimum arc to be used in conjunction with the different sizes of slides, may also be expressed in terms of the radius of curvature of the arcs. The arc is a circular segment and varies directly with the size of the slide. The relationship between the radius of curvature of the arc and the size of the slide is determined from the two following conditions: corresponding to the 18" slides, the radius of curvature is approximately 37.5 feet, while for the 42" slides the radius of curvature is approximately 250 feet. These two conditions may be employed to solve for the constant of proportionality in the relationship.

While this invention has been described in some detail, it will be understood by those skilled in the art that variations and modifications may be made Without departing from the spirit thereof or the scope of the following claims.

What is claimed is:

1. A slide comprising a plurality of interlocking and telescoping channel members having means for attachment to the under surface of separable, substantially aligned panels, each of said channel members having a curved arch along the longitudinal axis thereof to be normally higher near the center thereof than at the ends when said channel members are extended; and means to prevent disengagement of said channel members when said slide is extended.

2. A slide comprising a plurality of interlocking and telescoping channel members having means for attachment to the undersurface of separable, substantially aligned panels, each of said channel members having a curved arch along the longitudinal axis thereof to be normally higher near the center thereof than at the ends when said channel members are extended; said attachment means being located with respect to said slide on the opposite side of the radius of curvature of said arch and means to prevent disengagement of said channel members when said slide is extended.

3. A sheet metal slide comprising a plurality of interlocking and telescoping pre-stressed channel members having means for attachment to the under surface of separable, substantially aligned panels, each of said channel members having a curved arch along the longitudinal axis thereof to be normally higher near the center thereof than at the ends when said channel members are extended over a length of 38 to 42 inches, said slide being of 18" length and the height of said arch being within the range of values from 0.50" to 0.150" depending on the thickness of material employed in the construction of said slide; and means to prevent disengagement of said channel members when said slide is extended.

4. A sheet metal slide comprising a plurality of interlocking and telescoping pre-stressed channel members having means for attachment to the under surface of separable, substantially aligned panels, each of said channel members having a curved arch along the longtiudinal axis thereof to be normally higher near the center thereof than at the ends when said channel members are extended over a length of 38 to 42 inches, said slide being 21" length and the height of said arch being within the range of values from 0.075 to 0175" depending on the thickness of material employed in the construction of said slide; and means to prevent disengagement of said channel members when said slide is extended.

5. A sheet metal slide comprising a plurality of interlocking and telescoping pre-stressed channel members having means for attachment to the under surface of separable, substantially aligned panels, each of said channel members having a curved arch along the longitudinal axis thereof to be normally higher near the center thereof than at the ends when said channel members are extended over a length of 38 to 42 inches, said slide being 26" length and the height of said arch being within the range of values from 0.100 to 0.200" depending on the thickness of material employed in the construction of said slide; and means to prevent disengagement of said channel members when said slide is extended.

6. A sheet metal slide comprising a plurality of interlocking and telescoping pro-stressed channel members having means for attachment to the under surface of separable, substantially aligned panels, each of said channel members having a curved arch along the longitudinal axis thereof to be normally higher near the center thereof 1 than at the ends when said channel members are extended over a length of 38 to 42 inches, said slide being of 32" length and the height of said arch being within the range of values from 0.150" to 0.300" depending on the tmckness of material employed in the construction of said slide; and means to prevent disengagement of said channel members when said slide is extended.

7. The slide of claim 1 wherein said are is a circular segment the radius of curvature of which varies with the size of the slide, said radius of curvature being approximately 37.5 feet when said slide is of 18" length, and said radius of curvature being approximately 250 feet when said slide is of 42" length.

References Cited UNITED STATES PATENTS Vincent 108-83 Ingells 308-36 Hyland 308-3.8 Rudow et a1. 108--83 Duncan 10883 FRANCIS K. ZUGEL, Primary Examiner. 

1. A SLIDE COMPRISING A PLURALITY OF INTERLOCKING AND TELESCOPING CHANNEL MEMBERS HAVING MEANS FOR ATTACHMENT TO THE UNDER SURFACE OF SEPARABLE, SUBSTANTIALLY ALIGNED PANELS, EACH OF SAID CHANNEL MEMBERS HAVING A CURVED ARCH ALONG THE LONGITUDINAL AXIS THEREOF TO BE NORMALLY HIGHER NEAR THE CENTER THEREOF THAN AT THE ENDS WHEN SAID CHANNEL MEMBERS ARE EXTENDED; AND MEANS TO PREVENT DISENGAGEMENT OF SAID CHANNEL MEMBERS WHEN SAID SLIDE IS EXTENDED. 